This invention relates to means for identifying microorganisms such as bacteria to a desired level of specificity by releasing selected enzymes from the microorganisms and exposing them to a panel of immobilized dots of specific antibody, and then determining which of the dots bind the enzyme.
The simplest and most definitive modern microbial identification techniques rely on some form of probe technology that is either nucleic acid or antibody based. Among the most frequently applied of the new commercially available technologies is the RNA-DNA hybridization probe system. See e.g., D. E. Kohne "Applications of DNA Probe Tests to the Diagnosis of Infectious Disease", Amer. Prod. Rev., Nov. 20-29 (1986). With that system, a separate sample or probe must be processed for each of the species under consideration.
In recent years, solid-phase immunoassay techniques have been widely applied in basic research and clinical applications. To determine homogeneity or to identify unlabeled antigens, the classical methodologies of immunodiffusion and immunoelectrophoresis relying on precipitation have been available. More recently, as an extension of gel overlay techniques, the development methods for transferring proteins from the gel-phase of electrophoresis to a solid phase for immunoreaction permitted the optimal combination of high resolution of gel electrophoresis with the simplicity and sensitivity of solid-phase assays. One such methodology utilizes the transfer of proteins via direct application in the form of a dot. This type of methodology is frequently referred to as dot immunobinding, spot immunodetection or dot blot immunoassay. See e.g., H. Towbin and J. Gordon, "Immunoblotting and Dot Immunobinding-Current Status and Outlook" Journal of Immunological Methods 72:313-340 (1984).
In many antibody based immunodot procedures, a sandwich technique is usually required in which a standard primary ligand is applied to a membrane, which is then treated with the test sample. In order to visualize rapidly any binding that may occur, a third reagent, usually an antibody coupled to some standard enzyme, is applied next, and only then is a chromogenic substrate added that enables the visualization of the enzyme-antibody complex. See Towbin and Gordon, Id.
There is a need, however, for an accurate, rapid, and simple assay to differentiate or identify microorganisms. In particular, an assay kit that is simpler to construct, simpler to use, and less expensive would be highly desirable. The present invention is directed to such an assay.